Replaceable ignition unit for a recoilless gun cartridge

ABSTRACT

Cartridge cases provided with an ignition cap on their sidewalls usually require some device to transmit the ignition cap energy evenly to the full cross section of the powder charge and this invention includes a replaceable flange ring that enables a fullcaliber ignition unit housing to be introduced into the rear end of a cartridge case. This makes it easier to find the proper location of the ignition unit housing relative to the ignition cap. The cartridge case body can as a result, be used for several rounds.

United States Patent Inventor Ulf Edlund Eskilstuna, Sweden Appl. No. 847,188 Filed Aug. 4, 1969 Patented Oct. 19, 1971 Assignee Forsvarets Fabriksverk Eskilstuna, Sweden REPLACEABLE IGNITION UNIT FOR A RECOILLESS GUN CARTRIDGE 3 Claims, 1 Drawing Fig.

US. Cl

Int. Cl

Field orQ5111?"1131311311131 F421? l/l0 102/45, 24, 86.5, 90, 70, 44, 43, 39

[56] References Cited UNITED STATES PATENTS 3,291,050 12/1966 Ahlert et a1 102/90 3,3 75,656 4/1968 Hawkins 102/24 X 3,396,659 7/1968 Akhagen 102/45 X 3,446,146 5/1969 Stadler et al 102/86.5 X

Primary Examiner-Robert F. Stahl Att0rneyEric Y. Munson ABSTRACT: Cartridge cases provided with an ignition cap on their sidewalls usually require some device to transmit the ignition cap energy evenly to the full cross section of the powder charge and this invention includes a replaceable flange ring that enables a full-caliber ignition unit housing to be introduced into the rear end of a cartridge case. This makes it easier to find the proper location of the ignition unit housing relative to the ignition cap. The cartridge case body can as a result, be used for several rounds.

REPLACEABLE IGNITION UNIT FOR A RECOILLESS GUN CARTRIDGE BACKGROUND OF THE INVENTION 3,396,659 that a main full-caliber ignition housing be attached to the bottom of the cartridge case, said housing being internally provided with a thin-walled, subcaliber box containing the ignition charge. This charge is ignited by a flash from the ignition cap and hot gases, glowing remnants from the box, un burned powder etc., rush out into the empty outer portion of the ignition housing where the combustion of the powder is completed and the pressure and the heat are evenly distributed so that the main driving charge is ignited over its full cross section. This is accomplished through evenly distributed holes in the top wall of the ignition housing.

By the assembly of the present long cases of 90 mm. antiarmor shells, the ignition housing with a glued-on bottom plate has thus far been introduced through the front-end of the case because such cases have fixed, inwardly directed bottom flanges. The housing and the plate are then turned and adjusted so that the ignition transmission hole comes directly in front of the ignition cap and the bottom plate is thereupon glued to the case.

It has been found that this manner of assembly is time consuming and that the inwardly directed flange of the case becomes so deformed during firing that the whole case must be discarded after about two rounds.

SUMMARY OF THE INVENTION The present invention includes a simple locking ring that keeps the ignition housing and its bottom plate together as a unit that can be installed within the cartridge case from behind. The locking ring can, when damaged, be loosened by means of a few screws and it can be replaced so that the case body can be used several times.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawing, the FIG. shows an embodiment of the invention with the main parts thereof in separated relationship and in longitudinal perspective section.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, an ignition unit housing is shown at 2 and the same is provided with a coaxially located inner compartment or chamber 2a in the form of a thin-walled box that is filled with an ignition charge composition 9 and is closed at one end by a cover 8. The housing 2 is, by means of a flange and a groove, attached to the edge of a flat-bottom plate 7 with a groove around its peripheral edge for an axially tightening O-ring 6. This ring abuts against the inside of a locking ring 3 that fits over the junction between the plate 7 and the housing 2 and also over a small flange 11 or ridge on the outside of the housing 2, said flange being engaged with a groove 14a on the inside of the locking ring 3. The ring 3 is provided at one end with an inwardly directed flange 12 that abuts against the edge of the lower surface 16 of the bottom disk 7.

The cartridge case that is shown at I has in its rear end an inner, widened section 13 of an internal diameter corresponding to the outer diameter of the unit that is composed of the locking ring 3, the housing 2 and the plate 7. The widened section 13 has a marked, somewhat reinforced leading edge. The said unit is introduced from behind into the widened section 13 until it touches the said leading edge and it is turned or rotatively moved so that the hole for the ignition flash comes directly in front of a radial hole in the cartridge case where an ignition or striker cap 10 is inserted. The bottom unit is locked in this Iposition by apumber of locking screws 5 which enter throug radial ho es in the lower end portlon of the case I and extend into a somewhat conical groove 14 in the outside surface of the ring 3. The ring 3 also has a groove for a radially sealing O-ring 4.

When a round is fired, a flash from the striker cap 10 ignites the powder charge 9 whereby the walls of the box 20 will burst and hot gas, unburned powder and remnants of the box are fully combusted in an outer chamber, that is within the igni tion housing 2. The hot gases then attack through holes I5 provided in the top wall of the housing 2 and ignite the main driving charge. When the pressure in the case has increased sufficiently, the bottom plate 7 and the ignition unit will crack or burst and the remains are thrown out through the venturi or nozzle. The case can afterward be extracted in a normal mannerv The ring 3 is, if damaged, taken off by loosening the screws 5 and a new ring installed. There is no need for discarding the entire cartridge case. The case] and the ring 3 can both be made of brass. The housing 2 and the plate 7 can be made of easily frangible plastic, cardboard or the like.

The described construction can, of course, be applied to all cases intended for guns working on the back blower or recoilless principle. The particular joints and mounts shown and described herein can be made in numerous different ways.

What is claimed is:

1. A cartridge comprising: a cylindrical cartridge case having an ignition opening in a sidewall thereof at the rear of said case; an ignition unit within said cartridge case having an ignition opening aligned with the ignition opening in said cartridge case, said ignition unit insertable into the rear of said cartridge case; and a locking ring adjustably engaging said ignition unit and cartridge case to permit alignment of said ignition openings in said cartridge case and ignition unit.

2. A large bore cartridge as in claim 1 in which said locking ring is dimensioned to surround and engage the outer surface of said ignition unit, and to fit snugly within the rear end of said cartridge case to engage the interior surface thereof; and a setscrew extending through a threaded opening in said cartridge case sidewall to engage said ring.

3. A cartridge as in claim 2 in which said ring is formed with a groove in which said setscrew seats. 

1. A cartridge comprising: a cylindrical cartridge case having an ignition opening in a sidewall thereof at the rear of said case; an ignition unit within said cartridge case having an ignition opening aligned with the ignition opening in said cartridge case, said ignition unit insertable into the rear of said cartridge case; and a locking ring adjustably engaging said ignition unit and cartridge case to permit alignment of said ignition openings in said cartridge case and ignition unit.
 2. A large bore cartridge as in claim 1 in which said locking ring is dimensioned to surround and engage the outer surface of said ignition unit, and to fit snugly within the rear end of said cartridge case to engage the interior surface thereof; and a setscrew extending through a threaded opening in said cartridge case sidewall to engage said ring.
 3. A cartridge as in claim 2 in which said ring is formed with a groove in which said setscrew seats. 